Why is Lake Tahoe so blue?

Because of its purity and great depth, and the clarity of the atmosphere, all colors of the sky and landscape are reflected in Lake Tahoe. You can see why it is called the “Lake of the Sky,” with its brilliant shades of blues, greens and reds. Because it is so clear, the bottom adds shades to the blue; sand reflects as light blue, rock and deep canyons as virtually black.